Communication system



m Q, E932. F. s. ENTZ ET AL COMMUNICATION SYSTEM Filed Aug. 22, 1930 3 Sheets-Sheet 1 hsflvrz IN VENT 0R5 A.E.BACHELET I Aug. 9, 1932.

FIG. 2

F. S. ENTZ ET AL COMMUNICATION SYSTEM Filed Aug. 22. 1930 5 Sheets-Sheet 2 HIv H IIHI- F15. ENTZ 'NVENTORS A. E'BACHELET ATTORNEY Aug. 9, 1932. F. s. ENTZ ET AL 1,871,310

COMMUNICATION SYSTEM Filed Aug. 22. 1950 a Sheets-Sheet s IIHII INVENTORS Q izig ATTORNEY Patented Au 9, 1932 9mm STATES rnnnnmnn s.

.IPATENT orri'cs nnrz m ALBERT a. nominal, or new ions, at. r..- ASSIGNOBS 'ro BELL TELEPHONE LABORATORIES, INCORPORATED, OINEW YORK, N. YQ'A 003-;

reunion or mew Yonx communion srsrmr Application filed August 22,1930. semi in. 410,960;

. This invention relates to communication systems and particularly to switching arrangements for interconnecting incoming and outgoing communication channels.

5' In modern practice mostr'a dio broadcasting stations transmit programs which originate at points other than their own studios. There are a number of wire systems known, for example, as the red network, the purple 10 network, the blue network, the green network and so forth into which pro rams origi nating at different points'at di erent times are transmitted. A descriptionpf, these wire line systems is contained in the Bell System Technical Journal for January 1930, page 141 et. seq. Any one particular broadcasting station may connect at difierent times one or another of these networks to its transmitter so that switching arrangements must be rovided for makin the desired changes.

S ince time is essential both from the standpoint of continuity of broadcasting and from the standpoint of the advertiser the chan e from one network to another must be made as nearly instantaneously as possible.

H'eretofore these changes have been made manually through the medium of a plug and jack arrangement, but while this system has in the past proved satisfactory the burden on the operators is fast becoming intolerable. To continue the present system of switching means inevitably. that the period allowed for switchin will have to be lengthened whereas all e orts are being directed to produce the opposite effect. I h

It is the object of the present invention to provide means for quickly and accurately rearranging the interconnections of program supply circuits and program broadcasting circuits. For this purpose a number of networks which are here called incoming communication channels are brought to a central point together with a number of circuits lead ing directly to a number of broadcasting transmitter stations such circuits being here called outgoing communication channels.

1 Duplicate banks of keys are provided, one key in each bank for each crossing point of an incomin and an outgoing communication 50 channel. uring a given period one of these banks is effective and the incoming channels are connected to the outgoing channels in accordance with the keys which are operated. Durin this period the arrangement of channels w ich will be used during the next period may be set up on the other bank of keys. At the end of the first periodamaster 1ncoming channel switch for, each incoming channel is operated whereupon the preselect- 1 ed arrangement of the second bank of keys becomes immediately effective.

Accordingly one feature oftlie present invention is a duplicate set or. keys jor inter? connecting incoming and outgoing communication channels one of'which iseifective and the other of which is inefiective at any given time, whereby the'keys-o f the inefiective-set may. be operated in anycombination to prepare for an arrangement desired during the next ensuing period, I in combination with means for renderingeither set efiective.

In accordance with another feature there is a switching means associated with each incoming communication channel for renderiiztg the connections set up on either key set e ective, under control of the last previously com leted interconnection of channels. Stated dlfierently, this feature comprises switching means individual toeach channel for connectin the said channel to the one ke set or the ot er, the switching means of t e outgoing channels bein under control of the switching means of t e incoming channels.

For purposes of illustration we will designate the two key sets as the regular and the alternate sets respectively, the incoming communication channels as red, purple, blue and so forth and the outgoingv communication channels as one, two, three and so forth. Now

let us say that during the first period of time the keys of the regular set are operated to interconnect the red, the number one and number three channels and the purple and number two channels and the incoming chamnels keys of all incoming channels are set to render the regular key set effective. Let us say further that the schedule for the next en suing period calls for the interconnection of the red, the number one and number two channels and the blue and number three channels. Any time during the first eriod these .over for one minute. At the end of the .first period then the switching .means for the pur 1e and blue channels are operated to ren er the set up on the; alternate key set efi'ective. But outgoing channels one and threeare at this time connected to the red channel through the regular key set and hence the new connection between the blue and number three channel'as set up on the alternate key set does not become effective until the program on the red channel ceases and the red channel switching means is'operated toward the alternate key set.

In accordance with another feature of the invention there is provided signaling means for indicating the key set which is in use and the direction of change from one key set to the other. There are three signals, one associated directly with-each key set and another intermediate the'two. When a single one of thefirst two signals is displayed it in- .dicates that that particular key set is completely effective but when in addition the third signal is displayed it indicates that a chan is being made from that key set whose signs is displayed to that whose signal is not displays Other features will appear through the following description.

The drawings consist of three sheets marked Fig. 1, 2 and 3, respectively. Fig.

' Fig. 2 and Fig. 3 taken 1 is a schematic diagram to illustrate the manner .in which the apparatus operates.

ing placed above Fig. 2 form. a circuit diagram of the electrical connections of the apparatus forming the subject matter of this invention.

Consideringfirst Fig. 1, it will be noted that two banks of keys are provided, one

shown in the .upper part and the other shown in the lower art of the drawings. At the left there are indicated five incoming circuits denoted as red, purple, blue, green and orange. Each circuit enters a switching key such as 23, 24, 25, 26 and 27. The key 23 is used to switch the red circuit eitherfto the upper bank of keys overcircuit 28- or the lower bank of keys over the circuit 29. The

circuit 28 may be connected to any one, several or all of 16 outgoing circuits denoted 1 to 16, respectively.

- But let us assume that the program coming in over the red channel runs to their a ternate together, Fig. 3 be-- The switching keys are provided in oups, those numbered 17 to 22, inclusive, eing one group and being mechanically arranged so that when any one, such for instance as 17, is depressed, it will releaseany one of the others, such as 18, which may have been operated heretofore. By depressing one key in each of the vertical groups, the difierent colored network circuits may be connected to the different numbered outgoing circuits.

As'an illustration, we will assume that keys 17, and 31 are operated, so that with the network keys in the positions shown, the

red network will be connected throu h keys 17 and 31 'to outgoing circuits 1 and 3, respectively, and the purple network will be connected through key 30 to No. 2 outgoin circuit. For reasons which will be ex laineg hereinafter, when all of the networ keys 23 to 27, inclusive,

are in their normal positions, then all of the relays 32, 33, 34 etc.,

will be in their normal positions.

Let it be assumed that at a subsequent peri- -od it is desired to connect the red net work tooutgoing circuits 1 and 2 and the blue network to out oing circuit 3. At any time keys 35,36 and 37 may be depressed without in any way afiecting the connections established through the upper set of ke s.

At the roper time we will assume t at the network 0 s 24 to 27, inclusive, are moved ositions, but that the movement of the re network key 23 is delayed. During this delayed interval the con nection through ke 37 will be inefiective even though the b ue network key 25 has been moved to its alternate osition due to the fact that the red network key 23 still con trols the relay 34. The connection through key 36 will position where circuit 29 is active. Atthe end of this delay period when key 23 is thrown to its alternate position, then the connection throu h keys 35, 36 and 37 will all become imme iately effective.

The marked R are for releasing purposes, so that if during the middle of the program it is desired to disconnect the red network from outgoing circuit No. 1, then the key 22 is depressed so as to release key 17. A

To the left of these two sets of keys are shown three signal lamps R, C and A. When all of the keys 23 to 27, inclusive, are in the positions shown on the drawings, then the signal lamp R will be efiective. During the period after keys 24 to 27, inclusive have been thrown to their alternate positions, but key 23 has not yet been so moved, signal lamp 0 in addition to signal lamp R will operate. W'hen finally key 23 is thrown to its alternate position so that all of the colored netbe inefiective because the red network key 23 has not been thrown to the bottom rowv of keys for each set I work keys are in their alternate positions,

keys, then lamps A and C will glow during will the change-over operation and lamplR be as en finally glow alone when the change completed.

The circuit for this signal lamp arrangement is shown .in detail in Figs. 2 and 3. With all of the keys 23 to 27 in their normal positions a circuit is established from ground through the normal contacts of these keys to conductor 38 leading through the wind ing of relay 39 to batter Relay 39 is energized in this circuit an establishes a path from ground, the upper armature and front contact of relay 39, signal lamp R, back contact and upper armature of relay 40 to battery. When, for instance, key 24 is thrown to its alternate position then conductor 41 is grounded and a circuit is established from this ground through signal lamp C, the lower armature and front contact of relay 39 to battery, so that at this time both sigal lamps R and C will glow. When finally all of the keys 23 to 27 have been thrown to their alternate positions, then the ground on condoctor 38 is removed and relay 39 releases.

. U on the release of this relay a circuit is esta lished from ground,the upper armature and back contact of relay 39, winding of relay 40 to battery. Relay 4O 1n moving its armatures, closes a circuit through its front contact and upper armature for signal lamp A. Since the armatures of relay 39 have returned to their normal positions, the circuits for lamps R and G are broken and both of these lam s have become dark.

When in the process of change back to the normal positions of keys 23 to 27, any one of the keys is put into its normal position, then ground is again put on conductor 38 to cause the energization of relay 39. Relay 39 operates its armatures, but relay 40 is held locked in a circuit through its front contact and lower armature to the ground which is still on conductor 41. As long as relay 40 remains operated, lamp A will glow and with relay 39 also operated a circuit is established from the ground on conductor 41, through. lamp C, the lower armature and front contact or relay 39 to cause lamp C also to glow. When finally all keys 23 to 27 have been restored to their normal conditions, then the ground on conductor 41 is removed and the locking circuit of relay 40 is opened, so that the condition originally described is again established whereby lamp R alone is operated.

With red network key 23 in its normal position, the red circuit is connected through normal contacts of key 23 to circuit 28 and thence to the primary winding of transformer 42. The secondary of this transformer supplies a circuit 43 which leads to the contacts of keys 17 ,44, etc. Between the circuit 43 and the keys just mentioned, there are placed protective networks, such as 45 and 46 and in the normal position of these keys a load network 47 is connected to the circuit 43. When the key 17 has been operated the load network 47 is disconnected from the. circuit 43 and in place thereof the load comprising the circuit normally connected to circuit 1 is substituted. Thus the load on circuit 43 is maintained at a constant level.

The load network 48 is placed across circuit 51 while relay 49 is at normal position so that the load on the circuit leading from the secondary of transformer 50 may be maintained at a constant level and this lead network remains so connected until relays and 49 are operated to switch the outgoing circuit 1 from circuit 43 to circuit 50.

Normally a circuit extends from ground 2 through the extra cont-acts of key 21 and thence in series through the extra contacts of keys 20, 19, 18 and 17 to the windings of work key 23 is operated. to its alternate posi tion, then the series circuit through the extra. contacts of keys 21, 20, 19 and 18 will be closed through the extreme ri ht hand pair of contacts of key 23 to the windings of'relays 32 and 49 in parallel, so that now relay 32 ext-ends the circuit 51 to the out oing circuit 1. Relays 32 and 49 are now loc ed through the right hand armature and front contact of relay 49, the extra contacts of key 35 and j thence through the operated contacts of'key 23 to round, so that from now on no matter which one of the keys 1? to 21 is operated, the relay 32 will remain operated until either one of the keys 23 or 35 has been restored to its normal condition.

What is claimed is:

1. in a communication system, incoming and outgoing communication channels, a first and a second set of keys for interior: necting said incoming and said outgoing channels, and switching means common to both said sets of keys for alternatively rendering said key sets efiective.

2. In a communication system, incoming and outgoing communication channels, a first and a second set of keys for interconnectits ing said incoming and said outgoing channels, a manual switching arrangement indi' vidual to each said incomin channel for alternatively connecting'said c annel to said I first or said second key sets and an automatic switching arrangement individual to each said outgoing channel for alternatively connecting said channel to said first or said second key sets.

5 3. In a communication system incoming and outgoing communication c annels, a first and a second set of keys for interconnecting said incoming and said outgoing channels, a switching arrangement individual to each said incomm channel for alternatively connectin said incoming channel to said first or'sai second key set, and means under control of said'switching arrangements for alternatively connecting said outgoing channels to said first or said second key sets'. 4. In a communication system, incoming and outgoing communication channels, a first and a second set of keys for interconnectk, in said incoming and said outgoing channe s, a switching arrangement individual to. each said incomlng channel for alternatively connecting said incoming channel to said first or said second key set, a switchin arran ement individual to each outgoing c annel or alternatively conneetin said outgoing channel to said first or sai second key set, and means under control of said individual in-. comin channel switching means for controlling said individual outgoing channelswitching means.

5. In a communication system incoming and outgoing communicatlon c annels, a first and second set of keys for interconnecting said incoming and said outgoing channels, means for alternatively rendering said key sets effective, signaling means for indicating which key set is efiective and signaling means for indicating the direction of change during the operation of said first means.

6. In a communication system, incoming and outgoing communication channels, a first and a second key set for interconnecting said incoming and said outgoing channels, means individual to each said channel to connect said channel alternatively to said first or said second key set, a signal individual to X each said key set and means to display one of the said signals when all channels are connected to the corresponding key set, an auxiliary signal and means to display said auxiliary signal in addition to said other displayed signal when a fraction of said connecting means have been operated to connect the corresponding channels to the other said key set.

In wltness whereof, we'hereunto subscribe our names this 19th day of August, 1930.

FERDINAND S. ENTZ, ALBERT E. BAGHELET. 

